Exhaust gas treatment systems, particularly for vehicles having a diesel engine, may include a Selective Catalytic Reduction (SCR) catalytic converter. The SCR catalytic converter reacts with a reductant, which is introduced into a flow of exhaust gas, by an injector disposed upstream of the SCR catalytic converter. The reductant reacts with the nitric oxides in the exhaust gas over a catalyst in the SCR catalytic converter to convert the nitric oxides in the exhaust gas into nitrogen and water. The reductant may include a mixture of urea and water. The exhaust gas treatment system includes a mixer, which is disposed downstream of the reductant injector, and upstream of the SCR catalytic converter. The mixer mixes and/or vaporizes the reductant into the flow of exhaust gas.